The present invention relates to the decoration of bottles and the like, and more particularly to decoration of bottles by means of heat transfer labelling.
Decorating systems using heat transfer labels have received widespread commercial acceptance over the last decade. Such decorating systems are typically characterized by conveyors for feeding the objects to be labelled, usually bottles; a turret for sequentially positioning the bottles at a labelling station; a feed mechanism for transporting labels supported by a carrier strip to the labelling station, and a device for pressing a label against an adjacent bottle at the labelling station. Examples of such systems appear in U.S. Pat. Nos. 2,981,432; 3,036,624; 3,064,714; 3,208,897; 3,231,448; 3,261,734; 3,313,667; 3,709,755; and 3,861,986.
A particular requirement in designing turrets which may be used in labelling non-rigid articles, such as plastic bottles, is that some means be included to maintain the shape of the bottle during the label transfer, which typically involves significant pressures on the bottle face. A solution which has been widely adopted to meet this problem is the inclusion of a device to inflate the bottles during transfer, thus maintaining their shape through internal air pressure. Such devices are exemplified by that disclosed in U.S. Pat. No. 3,064,714 (cf. FIG. 5; cols. 3,4). Any inflating device must be synchronized in operation with the remainder of the labelling apparatus. It is desirable that the controlling apparatus for such inflating devices operate quickly and reliably. Furthermore, well-designed inflation control apparatus should be usable with turrets of different sizes and constructions. Inflation apparatus in the prior art inadequately satisfies these criteria.
Typical label carrier feed apparatus utilizing a method which is adopted in principle in the carrier transport of the invention is disclosed in U.S. Pat. No. 3,208,897. The main constituents of this type of transport are the label-bearing carrier strip, feed and guide rolls (the latter are dancer and idler rolls), a meter roll, two shuttle rolls, and cams with followers regulating the motion of the shuttle rolls.
The feed mechanism for transporting the carrier strip with labels to and from the labelling area must be carefully timed so that during labelling the carrier strip will be moving at the same speed as the tangential speed of the bottle to be decorated. The linear speed of the pressing means, label-carrier strip, and bottle surface is a critical limiting factor in heat transfer labelling; the quality of the transfer deteriorates if this speed is too high.
In the carrier strip transport systems typified by that disclosed in the above patent, the carrier strip speed is regulated by establishing a basic strip speed (registered by the meter roll) which represents a desired average rate of advance over the entire labelling cycle, and modifying this basic strip speed in the region of transfer so that it equals the more rapid linear speed of the bottle surface during transfer. The user may space the transfer labels fairly closely together on the carrier strip, as the same speed modifying means retards the advance of the carrier strip between labelling periods. The shuttle rolls and cams regulating their motion are used to locally modify the basic carrier transport speed. In all of these prior art decorating devices, "dwells" or idle periods are included in the rotation of the turrets in order to facilitate the loading and unloading of articles to be decorated. This requires a retarding period in the strip speed modifying means which is equal in duration to the accelerating period, and presents a severe limiting factor in the production rates of these decorators. Furthermore, the reciprocating motion of such prior art shuttle rolls is of undesirably large amplitude. This generally requires larger components and introduces greater disturbing forces, thus causing significantly increased mechanical problems. Ultimately, this imposes speed limitations on the carrier transport.
Accordingly, it is a principal object of the invention to provide decorating apparatus of the type described above with increased efficiency and higher production rates. A related object of the invention is to provide more reliable mechanical operations in such apparatus.
Another object of the invention is to achieve a turret with improved inflating apparatus for non-rigid articles to be labelled. A related object of the invention is to provide inflating apparatus of rapid, timely operation. Another related object is to avoid the need to redesign such inflating apparatus when used in turrets of varying size or construction.
A further object of the invention is to incorporate into the decorating apparatus a label carrier strip transport which may be used in conjunction with a continuously rotating turret. A related object of the invention is to modify the carrier strip speed in the labelling area to provide a relatively long accelerating period during labelling and a relatively brief retarding period in the interim. Yet another object of the invention is to reduce the magnitude of the reciprocating shuttle roll motion.